Went here twice last winter. I still can't believe how cheap it is (1,000 won for 1h!) but that also means a lot of people and kids. I went late, at maybe 9 or 10, and there were still so many little kids!! Korean children definitely dont go to bed on time!
Anyway, you pay the entrance, get the skates, and enjoy for an hour. After about 20-30 minutes I left because the floor was starting to deteriorate (too many people through the whole day, even though they clean every hour, it is still bad). I would still rate is as a 4/5 because of the value for money.
I think it opens sometime in December until the beginning of february..so right no you will have to wait til next winter! (or go to a more expensive 365days skating rink like the one in Lotte)